IP Address Allocation System and Method

ABSTRACT

An internet protocol (IP) address allocation method includes receiving, by a forwarder, an address request sent by an external network element, where the address request includes a dynamic host configuration protocol (DHCP) request of user equipment (UE) and user characteristic information of the UE, acquiring, from a DHCP service network element according to the DHCP request, an IP address allocated to the UE, and acquiring first instruction information that is delivered by a control device according to the user characteristic information of the UE and the IP address allocated to the UE, and sending the IP address to the UE according to the user characteristic information.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/798,200 filed on Feb. 21, 2020, which is a continuation of U.S.patent application Ser. No. 14/979,380 filed on Dec. 27, 2015, now U.S.Pat. No. 10,574,626, which is a continuation of International PatentApplication No. PCT/CN2013/078068 filed on Jun. 26, 2013. All of theaforementioned patent applications are hereby incorporated by referencein their entireties.

TECHNICAL FIELD

Embodiments relate to the field of communications, and in particular, toan IP address allocation method and system.

BACKGROUND

Currently, in software-defined networking (SDN), a network switchingmodel protocol OPENFLOW, as a type of switching standard in an SDNnetwork, implements separation between a control plane and a forwardingplane. Based on the standard OPENFLOW, main components of the SDNnetwork includes a forwarder supporting OPENFLOW and a control deviceconfigured to manage a switching device, where a forwarding behavior ofthe forwarder is determined by the control device.

After the SDN using the standard OPENFLOW is introduced into a systemarchitecture evolution (SAE) architecture, after receiving a DynamicHost Configuration Protocol (DHCP) request sent by a user side, theforwarder cannot respond to the request, causing that a user cannotacquire an address in a DHCP manner.

SUMMARY

Embodiments of the present disclosure provide an internet protocol (IP)address allocation system and method, which implement, if a controldevice is separated from a forwarder, a function that enables a user toacquire an IP address in a DHCP manner, and compared with otherapproaches, overcome an disadvantage that a user cannot acquire anaddress in a DHCP manner in an SAE network architecture of SDN.

In order to achieve the foregoing objectives, technical solutions usedin the embodiments of the present disclosure are as follows.

According to a first aspect, an embodiment of the present disclosureprovides a forwarder, applied in a system in which a control plane isseparated from a forwarding plane, including a communications unit,configured to communicate with an external network element, and aprocessor, configured to receive, by using the communications unit, anaddress request sent by the external network element, where the addressrequest includes a DHCP request of user equipment (UE) and usercharacteristic information of the UE, acquire, from a DHCP servicenetwork element according to the DHCP request, an IP address allocatedto the UE, acquire, by using the communications unit, first instructioninformation that is delivered by a control device according to the usercharacteristic information of the UE and the IP address allocated to theUE, wherein the first instruction information is used to indicatesending, when a packet whose destination address is the IP address isreceived, the packet to the UE according to the user characteristicinformation, and send the IP address to the UE according to the usercharacteristic information by using the communications unit.

With reference to the first aspect, in a first possible implementationmanner, that the processor is configured to acquire, from a DHCP servicenetwork element according to the DHCP request, an IP address allocatedto the UE specifically includes the processor is configured to send theDHCP request to the DHCP service network element by using thecommunications unit, and receive, by using the communications unit, aDHCP request response sent by the DHCP service network element, wherethe DHCP request response includes the IP address allocated to the UE,and a destination address of the DHCP request response is the IP addressallocated to the UE, and that the processor is configured to send the IPaddress to the UE according to the user characteristic information byusing the communications unit specifically includes the processor isconfigured to send the DHCP request response to the UE according to thefirst instruction information by using the communications unit.

With reference to the first aspect or the first possible implementationmanner, in a second possible implementation manner, that the processoris configured to acquire, from a DHCP service network element accordingto the DHCP request, an IP address allocated to the UE, and acquire, byusing the communications unit, first instruction information that isdelivered by a control device according to the user characteristicinformation of the UE and the IP address allocated to the UEspecifically includes the processor is configured to send the DHCPrequest and the user characteristic information of the UE to the controldevice by using the communications unit, where the control devicesupports a DHCP service, and receive, by using the communications unit,the IP address allocated to the UE and the first instruction informationthat are sent by the control device.

With reference to the first aspect or the first possible implementationmanner, in a third possible implementation manner, that the processor isconfigured to acquire, from a DHCP service network element according tothe DHCP request, an IP address allocated to the UE specificallyincludes the processor is configured to send the DHCP request to a DHCPserver by using the communications unit, and receive, by using thecommunications unit, the IP address allocated by the DHCP server to theUE, and that the processor is configured to acquire first instructioninformation that is delivered by a control device according to the usercharacteristic information of the UE and the IP address allocated to theUE specifically includes the processor is configured to send, by usingthe communications unit, the IP address allocated to the UE and the usercharacteristic information of the UE to the control device, and receive,by using the communications unit, the first instruction information thatis delivered by the control device according to the IP address allocatedto the UE and the user characteristic information of the UE.

With reference to the third possible implementation manner, in a fourthpossible implementation manner, the processor is further configured tosend the DHCP request to the control device by using the communicationsunit, and receive, by using the communications unit, second instructioninformation sent by the control device, where the second instructioninformation is used to indicate forwarding, when the DHCP request isreceived, the DHCP request to the DHCP server, and that the processor isconfigured to send the DHCP request to a DHCP server by using thecommunications unit specifically includes the processor is configured tosend the DHCP request to the DHCP server according to the secondinstruction information by using the communications unit.

According to a second aspect, an embodiment of the present disclosureprovides a control device, applied in a system in which a control planeis separated from a forwarding plane, including a communications unit,configured to communicate with an external network element, and aprocessor, configured to acquire user characteristic information of UEand an IP address allocated to the UE, and send first instructioninformation to a forwarder by using the communications unit, where thefirst instruction information is used to instruct the forwarder to send,when a packet whose destination address is the IP address is received,the packet to the UE according to the user characteristic information,where the forwarder is controlled by the control device.

With reference to the second aspect, in a first possible implementationmanner, that the processor is configured to acquire user characteristicinformation of UE and an IP address allocated to the UE specificallyincludes the processor is configured to receive, by using thecommunications unit, a DHCP request of the UE and the usercharacteristic information of the UE that are sent by the forwarder,where the control device supports a DHCP service, allocate the IPaddress to the UE, and deliver, by using the communications unitaccording to the user characteristic information of the UE and the IPaddress allocated to the UE, the IP address allocated to the UE and thefirst instruction information to the forwarder.

With reference to the second aspect, in a second possible implementationmanner, that the processor is configured to acquire user characteristicinformation of UE and an IP address allocated to the UE specificallyincludes the processor is configured to receive, by using thecommunications unit, the IP address allocated to the UE and the usercharacteristic information of the UE that are sent by the forwarder, anddeliver the first instruction information to the forwarder according tothe IP address allocated to the UE and the user characteristicinformation of the UE.

With reference to the second possible implementation manner, in a thirdpossible implementation manner, the processor is further configured toreceive, by using the communications unit, a DHCP request of the UE thatis sent by the forwarder, and send second instruction information to theforwarder by using the communications unit, where the second instructioninformation is used to instruct the forwarder to forward, when the DHCPrequest is received, the DHCP request to a DHCP server.

According to a third aspect, an embodiment of the present disclosureprovides an address allocation method, applied in a system in which acontrol plane is separated from a forwarding plane, including receiving,by a forwarder, an address request sent by an external network element,where the address request includes a DHCP request of UE and usercharacteristic information of the UE, acquiring, by the forwarder from aDHCP service network element according to the DHCP request, an IPaddress allocated to the UE, acquiring, by the forwarder, firstinstruction information that is delivered by a control device accordingto the user characteristic information of the UE and the IP addressallocated to the UE, where the first instruction information is used toindicate sending, when a packet whose destination address is the IPaddress is received, the packet to the UE according to the usercharacteristic information, and sending, by the forwarder, the IPaddress to the UE according to the user characteristic information.

With reference to the third aspect, in a first possible implementationmanner, the acquiring, by the forwarder from a DHCP service networkelement according to the DHCP request, an IP address allocated to the UEspecifically includes sending, by the forwarder, the DHCP request to theDHCP service network element, and receiving a DHCP request response sentby the DHCP service network element, where the DHCP request responseincludes the IP address allocated to the UE, and a destination addressof the DHCP request response is the IP address allocated to the UE, andthe sending, by the forwarder, the IP address to the UE according to theuser characteristic information specifically includes sending, by theforwarder, the DHCP request response to the UE according to the firstinstruction information.

With reference to the third aspect or the first possible implementationmanner, in a second possible implementation manner, the acquiring, bythe forwarder from a DHCP service network element according to the DHCPrequest, an IP address allocated to the UE, and the acquiring, by theforwarder, first instruction information that is delivered by a controldevice according to the user characteristic information of the UE andthe IP address allocated to the UE specifically include sending, by theforwarder, the DHCP request and the user characteristic information ofthe UE to the control device, where the control device supports a DHCPservice, and receiving, by the forwarder, the IP address allocated tothe UE and the first instruction information that are sent by thecontrol device.

With reference to the third aspect or the first possible implementationmanner, in a third possible implementation manner, the acquiring, by theforwarder from a DHCP service network element according to the DHCPrequest, an IP address allocated to the UE specifically includessending, by the forwarder, the DHCP request to a DHCP server, andreceiving, by the forwarder, the IP address allocated by the DHCP serverto the UE, and the acquiring, by the forwarder, first instructioninformation that is delivered by a control device according to the usercharacteristic information of the UE and the IP address allocated to theUE specifically includes sending, by the forwarder, the IP addressallocated to the UE and the user characteristic information of the UE tothe control device, and receiving the first instruction information thatis delivered by the control device according to the IP address allocatedto the UE and the user characteristic information of the UE.

With reference to the third possible implementation manner, in a fourthpossible implementation manner, the sending, by the forwarder, the DHCPrequest to a DHCP server specifically includes sending, by theforwarder, the DHCP request to the control device, and receiving, by theforwarder, second instruction information sent by the control device,where the second instruction information is used to indicate forwarding,when the DHCP request is received, the DHCP request to the DHCP server,and the sending, by the forwarder, the DHCP request to a DHCP serverspecifically includes sending, by the forwarder, the DHCP request to theDHCP server according to the second instruction information by using thecommunications unit.

According to a fourth aspect, an embodiment of the present disclosureprovides an address allocation method, applied in a system in which acontrol plane is separated from a forwarding plane, including acquiring,by a control device, user characteristic information of UE and an IPaddress allocated to the UE, and sending, by the control device, firstinstruction information to a forwarder, where the first instructioninformation is used to instruct the forwarder to send, when a packetwhose destination address is the IP address is received, the packet tothe UE according to the user characteristic information, where theforwarder is controlled by the control device.

With reference to the fourth aspect, in a first possible implementationmanner, the acquiring, by a control device, user characteristicinformation of UE and an IP address allocated to the UE specificallyincludes receiving, by the control device, a DHCP request of the UE andthe user characteristic information of the UE that are sent by theforwarder, where the control device supports a DHCP service, allocating,by the control device, the IP address to the UE, and delivering, by thecontrol device according to the user characteristic information of theUE and the IP address allocated to the UE, the IP address allocated tothe UE and the first instruction information to the forwarder.

With reference to the fourth aspect, in a second possible implementationmanner, the acquiring, by a control device, user characteristicinformation of UE and an IP address allocated to the UE specificallyincludes receiving, by the control device, the IP address allocated tothe UE and the user characteristic information of the UE that are sentby the forwarder, and delivering the first instruction information tothe forwarder according to the IP address allocated to the UE and theuser characteristic information of the UE.

With reference to the second possible implementation manner, in a thirdpossible implementation manner, the receiving, by the control device,the IP address and the user characteristic information that are sent bythe forwarder specifically includes receiving, by the control device, aDHCP request of the UE that is sent by the forwarder, and sending, bythe control device, second instruction information to the forwarder,where the second instruction information is used to instruct theforwarder to forward, when the DHCP request is received, the DHCPrequest to a DHCP server.

According to a fifth aspect, a forwarder is provided, applied in asystem in which a control plane is separated from a forwarding plane,including a receiving unit, configured to receive an address requestsent by an external network element, where the address request includesa DHCP request of UE and user characteristic information of the UE, anacquiring unit, configured to acquire, from a DHCP service networkelement according to the DHCP request, an IP address allocated to theUE, where the acquiring unit is further configured to acquire firstinstruction information that is delivered by a control device accordingto the user characteristic information of the UE and the IP addressallocated to the UE, where the first instruction information is used toindicate sending, when a packet whose destination address is the IPaddress is received, the packet to the UE according to the usercharacteristic information, and a sending unit, configured to send theIP address to the UE according to the user characteristic information.

With reference to the fifth aspect, in a first possible implementationmanner, the acquiring unit is specifically configured to send the DHCPrequest to the DHCP service network element, and receive a DHCP requestresponse sent by the DHCP service network element, where the DHCPrequest response includes the IP address allocated to the UE, and adestination address of the DHCP request response is the IP addressallocated to the UE, and the sending unit is specifically configured tosend the DHCP request response to the UE according to the firstinstruction information.

With reference to the fifth aspect or the first possible implementationmanner, in a second possible implementation manner, the acquiring unitincludes a first sending subunit, configured to send the DHCP requestand the user characteristic information of the UE to the control device,where the control device supports a DHCP service, and a first receivingsubunit, configured to receive the IP address allocated to the UE andthe first instruction information that are sent by the control device.

With reference to the fifth aspect or the first possible implementationmanner, in a third possible implementation manner, the acquiring unitincludes a second sending subunit, configured to send the DHCP requestto a DHCP server, and a second receiving subunit, configured to receivethe IP address allocated by the DHCP server to the UE, where the secondsending subunit is further configured to send the IP address allocatedto the UE and the user characteristic information of the UE to thecontrol device, so that the control device delivers the firstinstruction information to the forwarder according to the IP address andthe user characteristic information, and the second receiving subunit isfurther configured to receive the first instruction information that isdelivered by the control device according to the IP address of the UEand the user characteristic information of the UE.

With reference to the third possible implementation manner, in a fourthpossible implementation manner, the sending unit is further configuredto send the DHCP request to the control device, the receiving unit isfurther configured to receive second instruction information sent by thecontrol device, where the second instruction information is used toindicate forwarding, when the DHCP request is received, the DHCP requestto the DHCP server, and the sending unit is further specificallyconfigured to send the DHCP request to the DHCP server according to thesecond instruction information.

According to a sixth aspect, a control device is provided, applied in asystem in which a control plane is separated from a forwarding plane,including an acquiring unit, configured to acquire user characteristicinformation of UE and an IP address allocated to the UE, and a sendingunit, configured to send first instruction information to a forwarder,where the first instruction information is used to instruct theforwarder to send, when a packet whose destination address is the IPaddress is received, the packet to the UE according to the usercharacteristic information, where the forwarder is controlled by thecontrol device.

With reference to the sixth aspect, in a first possible implementationmanner, the acquiring unit further includes a first receiving subunit,configured to receive a DHCP request of the UE and the usercharacteristic information of the UE that are sent by the forwarder,where the control device supports a DHCP service, an allocation subunit,configured to allocate the IP address to the UE, and a deliveringsubunit, configured to deliver the IP address allocated to the UE andthe first instruction information to the forwarder according to the usercharacteristic information of the UE and the IP address allocated to theUE.

With reference to the sixth aspect, in a second possible implementationmanner, the acquiring unit further includes a second receiving subunit,configured to receive the IP address allocated to the UE and the usercharacteristic information of the UE that are sent by the forwarder, anddeliver the first instruction information to the forwarder according tothe IP address allocated to the UE and the user characteristicinformation of the UE.

With reference to the second possible implementation manner, in a thirdpossible implementation manner, the second receiving subunit furtherincludes a receiving module, configured to receive a DHCP request of theUE that is sent by the forwarder, and a sending module, configured tosend second instruction information to the forwarder, where the secondinstruction information is used to instruct the forwarder to forward,when the DHCP request is received, the DHCP request to a DHCP server.

According to a seventh aspect, an embodiment of the present disclosureprovides a system in which a control plane is separated from aforwarding plane, including any forwarder according to the first aspectand any control device according to the second aspect, or including anyforwarder according to the fifth aspect and any control device accordingto the sixth aspect.

The embodiments of the present disclosure provide an IP addressallocation system and method, which implement, if a control device isseparated from a forwarder, a function that enables a user to acquire anIP address in a DHCP manner, and compared with other approaches,overcome an disadvantage that a user cannot acquire an address in a DHCPmanner in an SAE network architecture of SDN.

BRIEF DESCRIPTION OF THE DRAWINGS

To describe the technical solutions in the embodiments of the presentdisclosure more clearly, the following briefly introduces theaccompanying drawings required for describing the embodiments.Apparently, the accompanying drawings in the following description showmerely some embodiments of the present disclosure, and a person ofordinary skill in the art may still derive other drawings from theseaccompanying drawings without creative efforts.

FIG. 1 is a diagram of an SAE/long term evolution (LTE) networkarchitecture into which SDN is introduced.

FIG. 2 is a schematic flowchart of an address allocation methodaccording to an embodiment of the present disclosure.

FIG. 3 is a schematic flowchart of another address allocation methodaccording to an embodiment of the present disclosure.

FIG. 4 is a schematic flowchart of a detailed embodiment of an addressallocation method.

FIG. 5 is a schematic flowchart of another detailed embodiment of anaddress allocation method.

FIG. 6 is a schematic flowchart of a detailed embodiment of anotheraddress allocation method.

FIG. 7 is a schematic flowchart of another detailed embodiment ofanother address allocation method.

FIG. 8 is a schematic structural diagram of a forwarder according to anembodiment of the present disclosure.

FIG. 9 is a schematic structural diagram of another forwarder accordingto an embodiment of the present disclosure.

FIG. 10 is a schematic structural diagram of a control device accordingto an embodiment of the present disclosure.

FIG. 11 is a schematic structural diagram of another control deviceaccording to an embodiment of the present disclosure.

FIG. 12 is a schematic apparatus diagram of a forwarder according to anembodiment of the present disclosure.

FIG. 13 is a schematic apparatus diagram of a control device accordingto an embodiment of the present disclosure.

FIG. 14 is a schematic diagram of an IP address allocation systemaccording to an embodiment of the present disclosure.

DETAILED DESCRIPTION

The following clearly describes the technical solutions in theembodiments of the present disclosure with reference to the accompanyingdrawings in the embodiments of the present disclosure. Apparently, thedescribed embodiments are merely some but not all of the embodiments ofthe present disclosure. All other embodiments obtained by a person ofordinary skill in the art based on the embodiments of the presentdisclosure without creative efforts shall fall within the protectionscope of the present disclosure.

The method provided in the embodiments of the present disclosure may beapplied to various communications systems, such as a Global System forMobile Communications (GSM) network, a General Packet Radio Service(GPRS) network, a wideband code-division multiple access (WCDMA)network, a code-division multiple access (CDMA)-2000 network, a TimeDivision-Synchronous Code Division Multiple Access (TD-SCDMA) network,or a Worldwide Interoperability for Microwave Access (WiMAX) network.

In the present disclosure, a SAE/LTE network is used as an example fordescription. Certainly, the present disclosure is not limited toapplication in only this scenario.

Exemplarily, an SAE/LTE network may include two parts an access networkand a core network, where the access network includes UE and an evolvedNodeB (eNodeB), and the eNodeB is configured to provide the UE with anair interface, so that the UE accesses the SAE/LTE network. In theembodiments of the present disclosure, devices included in the accessnetwork make no contributions to technology improvements, therefore, thedevices included in the access network are collectively referred to as auser side. Key logical network elements of the core network include amobility management entity (MME), a serving gateway (S-GW), and a packetdata gateway (P-GW). The MME is configured to take charge of a controlfunction of the core network of the SAE/LTE network, and performmobility management and session management of UE. The S-GW and the P-GWmay be configured to provide a data transmission service for the userside. After the SDN is introduced into the foregoing SAE/LTE networkarchitecture, control functions and forwarding functions of the corenetwork elements are separated, and an SDN-based SAE/LTE networkarchitecture shown in FIG. 1 can be obtained, where a control deviceimplements control plane functions of the core network elements,including gateway control functions of the S-GW and the P-GW and afunction of the MME, and can perform configuration and management on aforwarder according to the OPENFLOW protocol, and the forwarderimplements forwarding plane functions of the core network elements,including gateway forwarding functions of the S-GW and the P-GW, and canprocess a data packet according to the configuration and managementperformed by the control device on the forwarder.

Refer to FIG. 2, which shows an address allocation method provided in anembodiment of the present disclosure. The address allocation method isapplied in a system in which a control plane is separated from aforwarding plane, and includes.

201. A forwarder receives an address request sent by an external networkelement, where the address request includes a DHCP request of UE anduser characteristic information of the UE.

202. The forwarder acquires, from a DHCP service network elementaccording to the DHCP request, an IP address allocated to the UE.

203. The forwarder acquires first instruction information that isdelivered by a control device according to the user characteristicinformation of the UE and the IP address allocated to the UE, where thefirst instruction information is used to indicate sending, when a packetwhose destination address is the IP address is received, the packet tothe UE according to the user characteristic information, where thecontrol device is a device controlling the forwarder.

204. The forwarder sends the IP address to the UE according to the usercharacteristic information.

Exemplarily, the acquiring, by the forwarder from a DHCP service networkelement according to the DHCP request, an IP address allocated to the UEspecifically includes sending, by the forwarder, the DHCP request to theDHCP service network element, and receiving a DHCP request response sentby the DHCP service network element, where the DHCP request responseincludes the IP address allocated to the UE, and a destination addressof the DHCP request response is the IP address allocated to the UE, andthe sending, by the forwarder, the IP address to the UE according to theuser characteristic information specifically includes sending, by theforwarder, the DHCP request response to the UE according to the firstinstruction information.

Optionally, the acquiring, by the forwarder from a DHCP service networkelement according to the DHCP request, an IP address allocated to theUE, and the acquiring, by the forwarder, first instruction informationthat is delivered by a control device according to the usercharacteristic information of the UE and the IP address allocated to theUE specifically include sending, by the forwarder, the DHCP request andthe user characteristic information of the UE to the control device,where the control device supports a DHCP service, and receiving, by theforwarder, the IP address allocated to the UE and the first instructioninformation that are sent by the control device.

Optionally, the acquiring, by the forwarder from a DHCP service networkelement according to the DHCP request, an IP address allocated to the UEspecifically includes sending, by the forwarder, the DHCP request to aDHCP server, and receiving, by the forwarder, the IP address allocatedby the DHCP server to the UE, and the acquiring, by the forwarder, firstinstruction information that is delivered by a control device accordingto the user characteristic information of the UE and the IP addressallocated to the UE specifically includes sending, by the forwarder, theIP address allocated to the UE and the user characteristic informationof the UE to the control device, and receiving the first instructioninformation that is delivered by the control device according to the IPaddress allocated to the UE and the user characteristic information ofthe UE. Further, the sending, by the forwarder, the DHCP request to aDHCP server specifically includes sending, by the forwarder, the DHCPrequest to the control device, and receiving, by the forwarder, secondinstruction information sent by the control device, where the secondinstruction information is used to indicate forwarding, when the DHCPrequest is received, the DHCP request to the DHCP server, and thesending, by the forwarder, the DHCP request to a DHCP serverspecifically includes sending, by the forwarder, the DHCP request to theDHCP server according to the second instruction information by using thecommunications unit.

This embodiment provides an IP address allocation method, whichimplements, if a control plane is separated from a forwarding plane, afunction that enables a user to acquire an IP address in a DHCP manner,and compared with other approaches, overcomes an disadvantage that auser cannot acquire an address in a DHCP manner in an SAE networkarchitecture of SDN.

Refer to FIG. 3, which shows another address allocation method providedin an embodiment of the present disclosure. The address allocationmethod is applied in a system in which a control plane is separated froma forwarding plane, and includes.

301. A control device acquires user characteristic information of UE andan IP address allocated to the UE.

Exemplarily, the acquiring, by a control device, user characteristicinformation of UE and an IP address allocated to the UE may specificallyinclude receiving, by the control device, a DHCP request of the UE andthe user characteristic information of the UE that are sent by aforwarder, where the control device supports a DHCP service, allocating,by the control device, the IP address to the UE, and delivering, by thecontrol device according to the user characteristic information of theUE and the IP address allocated to the UE, the IP address allocated tothe UE and first instruction information to the forwarder, or receiving,by the control device, the IP address allocated to the UE and the usercharacteristic information of the UE that are sent by a forwarder, anddelivering first instruction information to the forwarder according tothe IP address allocated to the UE and the user characteristicinformation of the UE. Further, the acquiring, by a control device, usercharacteristic information of UE and an IP address allocated to the UEmay further specifically include receiving, by the control device, aDHCP request of the UE that is sent by the forwarder, and sending, bythe control device, second instruction information to the forwarder,where the second instruction information is used to instruct theforwarder to forward, when the DHCP request is received, the DHCPrequest to a DHCP server.

302. The control device sends first instruction information to aforwarder, where the first instruction information is used to instructthe forwarder to send, when a packet whose destination address is the IPaddress is received, the packet to the UE according to the usercharacteristic information, where the forwarder is controlled by thecontrol device.

This embodiment provides an IP address allocation method, whichimplements, if a control plane is separated from a forwarding plane, afunction that enables a user to acquire an IP address in a DHCP manner,and compared with other approaches, overcomes an disadvantage that auser cannot acquire an address in a DHCP manner in an SAE networkarchitecture of SDN.

Based on the embodiments in FIG. 2 and FIG. 3, referring to FIG. 4, adetailed embodiment of an address allocation method is provided. Thisembodiment is characterized by that a DHCP service is integrated into acontrol device, and the control device may complete a DHCP addressallocation function or a DHCP address allocation device may be directlyconnected to the control device. Specific steps are as follows.

401. An external network element sends an address request to aforwarder.

Exemplarily, the address request includes a DHCP request of UE and usercharacteristic information of the UE. Specifically, in this embodimentof the present disclosure, after the UE sends a DHCP request packet toan eNodeB, the eNodeB encapsulates the user characteristic informationand the DHCP request packet of the UE into a GPRS Tunneling Protocol(GTP) packet, to obtain the address request. The user characteristicinformation is used to identify a user characteristic, and optionallyincludes, but is not limited to, tunnel endpoint identifier (TEID)information or a Media Access Control (MAC) address. Exemplarily, inthis embodiment of the present disclosure, the TEID information isselected as the user characteristic information.

402. The forwarder sends the address request to a control device.

Exemplarily, after the forwarder receives the address request, becausean uplink flow table related to the address request is not preinstalled,the forwarder cannot find, according to the address request, acorresponding flow table for matching, and therefore cannot process theaddress request. In this case, the forwarder may send all receivedpackets that do not match any flow table to the control device, and theaddress request is sent to the control device in this manner.

Further, referring to Table 1, a flow table may include a matchingfield, a counter, and an instruction set, where the matching field is a10-tuple, is an input keyword for packet matching, and may match 36types of fields, which are used for header field matching, in datapacket headers at five layers from an Ethernet layer to a transmissionlayer, the counter is used to collect statistical data of a flow entry,and the instruction set indicates an operation that should be performedon a data packet matching the flow entry, and the most basic operationbehaviors include forwarding a packet to a port, forwarding a packetafter encapsulating and rewriting the packet, and discarding a packet.

If a packet entering the forwarder has a field matching the matchingfield in the flow table, the forwarder performs an operation on thepacket according to the instruction set in the flow table, if a packetentering the forwarder has no field matching the matching field in theflow table, the forwarder may send the packet to the control device.Generation, maintenance, and delivery of the flow table are completelyimplemented by the control device.

TABLE 1 Flow table Matching field Counter Instruction set

Preferably, when the OPENFLOW protocol is used between the forwarder andthe control device, the forwarder may send the address request to thecontrol device by using a Packet-in message.

403. The control device acquires, according to the received addressrequest, user characteristic information of UE and an IP addressallocated to the UE.

Exemplarily, after receiving the Packet-in message sent by theforwarder, the control device performs GTP decapsulation on the message,to obtain the user characteristic information and the DHCP requestpacket of the UE, the control device hands over the DHCP request packetto a DHCP module, which is included in the control device, forprocessing, so that the DHCP module allocates the IP address to the UEaccording to the DHCP request packet, and encapsulates, into a DHCPrequest response, the IP address allocated to the UE. In addition, thecontrol device further maintains a relationship between an IP addressand user characteristic information, and specifically, the controldevice may maintain a correspondence between an IP address and usercharacteristic information in a form of a mapping table.

404. The control device sends the IP address allocated to the UE andfirst instruction information to the forwarder.

Exemplarily, the control device sends the DHCP request responseincluding the IP address allocated to the UE and the first instructioninformation to the forwarder, where the first instruction information isused to instruct the forwarder to send, after a packet whose destinationaddress is the IP address allocated to the UE is received, the packet tothe UE according to the user characteristic information. Specifically,the first instruction information may include a downlink flow table onwhich matching is performed by using the IP address allocated to the UE,so that the forwarder can send a downlink packet to a user using the IPaddress allocated to the UE. The DHCP request response in thisembodiment of the present disclosure belongs to a type of downlinkpacket.

It should be mentioned that the control device may further send anuplink flow table to the forwarder, and matching is performed on theuplink flow table according to the user characteristic information,because the IP address allocated to the UE corresponds to the usercharacteristic information, the uplink flow table enables the forwarderto process, according to the user characteristic information, an uplinkpacket sent by the UE that uses the IP address allocated to the UE.

405. The forwarder sends, to the UE according to the first indicationinformation, the IP address allocated to the UE.

Exemplarily, the first instruction information includes the downlinkflow table on which matching is performed by using the IP addressallocated to the UE. The forwarder may encapsulate the DHCP requestresponse and the user characteristic information together into a GTPpacket according to the downlink flow table, and send the GTP packet toan eNodeB, and finally the eNodeB decapsulates the GTP packet, and thensends the DHCP request response to the UE according to the usercharacteristic information, so that the UE acquires the IP address,which is allocated to the UE, in the DHCP request response, therebycompleting IP address allocation for the UE, and the UE can subsequentlyuse the IP address allocated to the UE for communication.

This embodiment provides an IP address allocation method, whichimplements, if a control plane is separated from a forwarding plane, afunction that enables a user to acquire an IP address in a DHCP manner,and compared with other approaches, overcomes an disadvantage that auser cannot acquire an address in a DHCP manner in an SAE networkarchitecture of SDN.

Based on the embodiments in FIG. 2 and FIG. 3, referring to FIG. 5,another detailed embodiment of an address allocation method is provided.Identical with the embodiment shown in FIG. 4, this embodiment ischaracterized by that a DHCP service is integrated into a controldevice, and the control device may complete a DHCP address allocationfunction or a DHCP address allocation device may be directly connectedto the control device. Preferably, in this embodiment, the DHCP addressallocation function is completed by the control device, and specificsteps are as follows.

501. A control device sends an uplink flow table to a forwarder.

Exemplarily, in this embodiment, each address request sent by UE belongsto an uplink packet, therefore, the control device may send the uplinkflow table to the forwarder in advance, so that the forwarder cancorrespondingly process an uplink packet according to the uplink flowtable. In this embodiment, the uplink flow table may include that theforwarder decapsulates a GTP packet of an address request, and if it isfound that a decapsulated GTP packet is a DHCP request packet, the DHCPrequest packet and TEID information in the GTP packet of the addressrequest are sent together to the control device.

502. An external network element sends an address request to theforwarder.

Exemplarily, this embodiment is similar to the embodiment described inFIG. 4, and the address request is obtained by an eNodeB byencapsulating user characteristic information and the DHCP requestpacket of the UE into the GTP packet. The user characteristicinformation is used to identify a user characteristic, and optionallyincludes TEID information or a MAC address. Exemplarily, in thisembodiment of the present disclosure, the TEID information is selectedas the user characteristic information.

503. The forwarder sends the address request to the control device.

Exemplarily, after receiving the address request, the forwarderdecapsulates the GTP packet of the address request according to theuplink flow table received in step 501, and if it is found that adecapsulated GTP packet is a DHCP request packet, the DHCP requestpacket and the TEID information in the GTP packet of the address requestare sent together to the control device.

504. The control device allocates an IP address to UE.

Exemplarily, a DHCP module included in the control device may allocate acorresponding IP address to a UE side according to the received DHCPrequest packet, and encapsulate the corresponding IP address into a DHCPrequest response, and the control device may map the IP addressallocated to the UE to the TEID information in a form of a mappingtable.

505. The control device sends the IP address allocated to the UE andfirst instruction information to the forwarder.

Exemplarily, the control device sends the IP address allocated to the UEand the first instruction information to the forwarder, where the IPaddress allocated to the UE may be included in the DHCP requestresponse. The first instruction information is used to instruct theforwarder to send, after a packet whose destination address is the IPaddress allocated to the UE is received, the packet to the UE accordingto the user characteristic information.

Specifically, the first instruction information may be indicated byusing the downlink flow table on which matching is performed by usingthe IP address in step 404 of the embodiment in FIG. 4, or the controldevice may encapsulate the DHCP request response into an addressresponse GTP packet, and send the address response GTP packet to theforwarder, where a TEID, which is included in a packet header, of the UEside is used as the first instruction information. In this embodiment,information obtained in the latter manner is selected as the firstinstruction information.

506. The forwarder sends, to a UE side according to the firstinstruction information, the IP address allocated to the UE.

Exemplarily, if the forwarder receives the address response GTP packetsent by the control device, the forwarder decapsulates the GTP packet toobtain the DHCP request response in the GTP packet, and directly sends,according to the TEID information included in the header of the addressresponse GTP packet, the DHCP request response to the UE sidecorresponding to the TEID information, so that the UE side acquires theIP address allocated to the UE.

This embodiment provides an IP address allocation method, whichimplements, if a control plane is separated from a forwarding plane, afunction that enables a user to acquire an IP address in a DHCP manner,and compared with other approaches, overcomes an disadvantage that auser cannot acquire an address in a DHCP manner in an SAE networkarchitecture of SDN.

Based on the embodiments in FIG. 2 and FIG. 3, referring to FIG. 6, adetailed embodiment of another address allocation method is provided.This embodiment is specifically characterized by that a DHCP addressallocation function is provided by a DHCP server outside a core network.Specific implementation steps are as follows.

601. An external network element sends an address request to aforwarder.

Exemplarily, similar to the embodiments in FIG. 4 and FIG. 5, theaddress request includes user characteristic information. Specifically,the address request sent by the external network element is obtained byan eNodeB by encapsulating a DHCP request packet of UE and the usercharacteristic information of the UE into a GTP packet. The usercharacteristic information is used to identify a user characteristic,and optionally includes TEID information or a MAC address. Preferably,in this embodiment, the TEID information is selected as the usercharacteristic information.

602. The forwarder sends the address request to a control device.

Exemplarily, because an uplink flow table related to the address requestis not preinstalled on the forwarder, the forwarder cannot find,according to the address request, a corresponding flow table formatching, and therefore cannot process the address request. In thiscase, the forwarder may send all received packets that do not match anyflow table to the control device, and the address request is sent to thecontrol device in this manner.

603. The control device acquires, according to the received addressrequest, user characteristic information of UE and sends secondinstruction information to the forwarder.

Exemplarily, the second instruction information may be specifically anuplink flow table sent by the control device to the forwarder, so thatthe forwarder can process the address request according to the uplinkflow table.

Specifically, after receiving the address request sent by the forwarder,the control device establishes an uplink flow table according to theDHCP request packet in the address request, so that the forwarder cansend the DHCP request packet to a DHCP server according to the uplinkflow table.

604. The forwarder sends the address request to a DHCP server accordingto the second instruction information.

Exemplarily, in this embodiment, the forwarder may decapsulate the GTPpacket of the address request according to the uplink flow table used asthe second instruction information, and send the DHCP request packet tothe DHCP server.

605. The DHCP server sends, to the forwarder, an IP address allocated tothe UE.

Exemplarily, after receiving the DHCP request packet, the DHCP serverallocates a corresponding IP address to a UE side, and the DHCP serverencapsulates, into a DHCP request response, the IP address allocated tothe UE, and sends the DHCP request response to the forwarder.

606. The forwarder sends the IP address allocated to the UE and the usercharacteristic information to the control device.

Exemplarily, because there is no corresponding downlink flow table,similar to step 602, the forwarder sends the received DHCP requestresponse that does not match any flow table to the control device forprocessing, and in order to enable the control device to identifyinformation about the UE side to which the IP address is allocated, theforwarder sends the DHCP request response and the corresponding usercharacteristic information together to the control device, so that thecontrol device delivers first instruction information to the forwarderaccording to the IP address allocated to the UE and the usercharacteristic information.

607. The control device sends the IP address allocated to the UE andfirst instruction information to the forwarder.

Exemplarily, the control device maps the IP address, which is allocatedto the UE, in the received DHCP request response to the usercharacteristic information in a form of a mapping table, to generate thefirst instruction information, where the first instruction informationis used to instruct the forwarder to send, after a packet whosedestination address is the IP address allocated to the UE is received,the packet to the UE according to the user characteristic information.

Specifically, the first instruction information may include a downlinkflow table on which matching is performed by using the IP addressallocated to the UE, so that the forwarder can send a downlink packet toa user using the IP address allocated to the UE. The DHCP requestresponse in this embodiment of the present disclosure belongs to a typeof downlink packet.

608. The forwarder sends, to a UE side according to the firstinstruction information, the IP address allocated to the UE.

Exemplarily, similar to step 405, the forwarder may encapsulate the DHCPrequest response and the user characteristic information together into aGTP packet according to the downlink flow table, and send the GTP packetto an eNodeB, and finally the eNodeB decapsulates the GTP packet, andthen sends the DHCP request response to the UE according to the usercharacteristic information, so that the UE acquires the IP address,which is allocated to the UE, in the DHCP request response, therebycompleting IP address allocation for the UE, and the UE can subsequentlyuse the IP address allocated to the UE for communication.

This embodiment provides an IP address allocation method, whichimplements, if a control plane is separated from a forwarding plane, afunction that enables a user to acquire an IP address in a DHCP manner,and compared with other approaches, overcomes a disadvantage that a usercannot acquire an address in a DHCP manner in an SAE networkarchitecture of SDN.

Based on the embodiments in FIG. 2 and FIG. 3, referring to FIG. 7,another detailed embodiment of another address allocation method isprovided. Identical with the embodiment shown in FIG. 6, this embodimentis characterized by that a DHCP address allocation function is providedby a DHCP server outside a core network. Specific steps are as follows.

701. A control device sends second instruction information to aforwarder in advance.

Exemplarily, the control device sends the second instruction informationto the forwarder in advance, where the second instruction informationincludes an uplink flow table, so that the forwarder can process anuplink packet sent by a user. Exemplarily, an address request sent by UEbelongs to a type of uplink packet.

702. An external network element sends an address request to theforwarder.

Exemplarily, similar to step 601 in the foregoing embodiment, theaddress request includes a DHCP request of the UE and usercharacteristic information of the UE, where the user characteristicinformation is used to identify a user characteristic, and optionallyincludes TEID information or a MAC address. Preferably, in thisembodiment, the TEID information is selected as the user characteristicinformation.

Specifically, the address request sent by the external network elementis obtained by an eNodeB by encapsulating a DHCP request packet of theUE and the user characteristic information of the UE into a GTP packet.

703. The forwarder sends the address request to a DHCP server accordingto the second instruction information.

Exemplarily, because the uplink flow table is preinstalled on theforwarder, the forwarder can process the received address request, andthe forwarder may decapsulate the GTP packet of the address requestaccording to the uplink flow table, and send the DHCP request packet tothe DHCP server.

704. The DHCP server sends, to the forwarder, an IP address allocated tothe UE.

Similar to step 605 in the foregoing embodiment, after receiving theDHCP request packet, the DHCP server allocates a corresponding IPaddress to the UE, and the DHCP server encapsulates, into a DHCP requestresponse, the IP address allocated to the UE, and sends the DHCP requestresponse to the forwarder.

705. The forwarder sends the IP address allocated to the UE and the usercharacteristic information to the control device.

Similar to step 606 in the foregoing embodiment, because there is nocorresponding downlink flow table, the forwarder sends the received DHCPrequest response that does not match any flow table to the controldevice for processing, and in order to enable the control device toidentify information about a UE side to which the IP address isallocated, the forwarder sends the DHCP request response and thecorresponding user characteristic information together to the controldevice, so that the control device delivers first instructioninformation to the forwarder according to the IP address allocated tothe UE and the user characteristic information.

706. The control device sends the IP address allocated to the UE andfirst instruction information to the forwarder.

Exemplarily, similar to step 607 in the foregoing embodiment, thecontrol device maps the IP address, which is allocated to the UE, in thereceived DHCP request response to the user characteristic information ina form of a mapping table, to generate the first instructioninformation, where the first instruction information is used to instructthe forwarder to send, after a packet whose destination address is theIP address allocated to the UE is received, the packet to the UEaccording to the user characteristic information.

Specifically, the first instruction information may include a downlinkflow table on which matching is performed by using the IP address, sothat the forwarder can send a downlink packet to a user using the IPaddress allocated to the UE. The DHCP request response in thisembodiment of the present disclosure belongs to a type of downlinkpacket.

707. The forwarder sends, to a UE side according to the firstinstruction information, the IP address allocated to the UE.

Exemplarily, similar to step 608 in the foregoing embodiment, theforwarder may encapsulate the DHCP request response and the usercharacteristic information together into a GTP packet according to thedownlink flow table, and send the GTP packet to an eNodeB, and finallythe eNodeB decapsulates the GTP packet, and then sends the DHCP requestresponse to the UE according to the user characteristic information, sothat the UE acquires the IP address, which is allocated to the UE, inthe DHCP request response, thereby completing IP address allocation forthe UE, and the UE can subsequently use the IP address forcommunication.

This embodiment provides an IP address allocation method, whichimplements, if a control plane is separated from a forwarding plane, afunction that enables a user to acquire an IP address in a DHCP manner,and compared with other approaches, overcomes a disadvantage that a usercannot acquire an address in a DHCP manner in an SAE networkarchitecture of SDN.

An embodiment of the present disclosure provides a forwarder 80, appliedin a system in which a control plane of SDN is separated from aforwarding plane. A specific form of the forwarder is not specificallylimited in this embodiment of the present disclosure, and the forwardermay be separate, or may be combined together with a control device. Asshown in FIG. 8, the forwarder 80 includes a receiving unit 801,configured to receive an address request sent by an external networkelement, where the address request includes a DHCP request of UE anduser characteristic information of the UE, an acquiring unit 802,configured to acquire, from a DHCP service network element according tothe DHCP request, an IP address allocated to the UE, where the acquiringunit 802 is further configured to acquire first instruction informationthat is delivered by a control device according to the usercharacteristic information of the UE and the IP address allocated to theUE, where the first instruction information is used to indicate sending,when a packet whose destination address is the IP address allocated tothe UE is received, the packet to the UE according to the usercharacteristic information, where the control device is a devicecontrolling the forwarder, and a sending unit 803, configured to send,to the UE according to the user characteristic information, the IPaddress allocated to the UE.

Exemplarily, in this embodiment of the present disclosure, after the UEsends a DHCP request packet to an eNodeB, the eNodeB encapsulates theuser characteristic information and the DHCP request packet into a GTPpacket, to obtain the address request. The user characteristicinformation is used to identify a user characteristic, and optionallyincludes TEID information or a MAC address. Exemplarily, in thisembodiment of the present disclosure, the TEID information is selectedas the user characteristic information.

Exemplarily, the acquiring unit 802 is further configured to send theDHCP request to the DHCP service network element, and receive a DHCPrequest response sent by the DHCP service network element, where theDHCP request response includes the IP address allocated to the UE, and adestination address of the DHCP request response is the IP addressallocated to the UE, and the sending unit 803 may be further configuredto send the DHCP request response to the UE according to the firstinstruction information.

Optionally, the first instruction information may include a downlinkflow table on which matching is performed by using the IP address. Thesending unit 803 may encapsulate the DHCP request response and the usercharacteristic information together into a GTP packet according to thedownlink flow table, and send the GTP packet to an eNodeB, and finallythe eNodeB decapsulates the GTP packet, and then sends the DHCP requestresponse to the UE according to the user characteristic information, sothat the UE acquires the IP address, which is allocated to the UE, inthe DHCP request response, thereby completing IP address allocation forthe UE.

Further, as shown in Table 1, a flow table may include a matching field,a counter, and an instruction set, where the matching field is a10-tuple, is an input keyword for packet matching, and may match 36types of fields, which are used for header field matching, in datapacket headers at five layers from an Ethernet layer to a transmissionlayer, the counter is used to collect statistical data of a flow entry,and the instruction set indicates an operation that should be performedon a data packet matching the flow entry, and the most basic operationbehaviors include forwarding a packet to a port, forwarding a packetafter encapsulating and rewriting the packet, and discarding a packet.

If a packet entering the forwarder 80 has a field matching the matchingfield in the flow table, the forwarder 80 performs an operation on thepacket according to the instruction set in the flow table, if a packetentering the forwarder 80 has no field matching the matching field inthe flow table, the forwarder 80 may send the packet to the controldevice. Generation, maintenance, and delivery of the flow table arecompletely implemented by the control device.

Optionally, the first instruction information may also be a packetheader including a TEID of the UE when the control device encapsulatesthe DHCP request response into an address response GTP packet, so thatthe sending unit 803 sends the address response GTP packet to thecorresponding UE according to the packet header including the TEID ofthe UE.

Exemplarily, referring to FIG. 9, the acquiring unit 802 may include afirst sending subunit 8021, configured to send the DHCP request and theuser characteristic information of the UE to the control device, wherethe control device supports a DHCP service, and a first receivingsubunit 8022, configured to receive the IP address allocated to the UEand the first instruction information that are sent by the controldevice.

Specifically, the first sending subunit 8021 may send the DHCP requestand the user characteristic information of the UE to the control deviceafter the forwarder 80 receives the address request, and because anuplink flow table related to the address request is not preinstalled,the forwarder 80 cannot find, according to the address request, acorresponding flow table for matching, and therefore cannot process theaddress request, and in this case, the forwarder 80 may send allreceived packets that do not match any flow table to the control device,and the address request is sent to the control device in this manner, orthe first sending subunit 8021 may send the DHCP request and the usercharacteristic information of the UE to the control device after thecontrol device sends an uplink flow table to the forwarder 80 inadvance, so that the first sending subunit 8021 can correspondinglyprocess an uplink packet according to the uplink flow table, and in thisembodiment, the uplink flow table may include that the forwarder 80decapsulates a GTP packet of the address request, and if it is foundthat a decapsulated GTP packet is a DHCP request packet, the DHCPrequest packet and the TEID information in the GTP packet of the addressrequest are sent together to the control device.

Exemplarily, referring to FIG. 9, the acquiring unit 802 may alsoinclude a second sending subunit 8023, configured to send the DHCPrequest to a DHCP server, and a second receiving subunit 8024,configured to receive the IP address that is allocated to the UE and issent by the DHCP server, where the second sending subunit 8023 isfurther configured to send the IP address allocated to the UE and theuser characteristic information of the UE to the control device, so thatthe control device delivers the first instruction information to theforwarder 80 according to the IP address allocated to the UE and theuser characteristic information.

Further, before the second sending subunit 8023 sends, to the DHCPserver, the request for acquiring an address of the UE, the sending unit803 is further configured to send the DHCP request of the UE to thecontrol device, and the receiving unit 801 is further configured toreceive second instruction information sent by the control device, wherethe second instruction information is used to indicate forwarding, whenthe address request of the UE is received, the DHCP request to the DHCPserver.

Specifically, the second instruction information may be an uplink flowtable sent by the control device to the forwarder 80, so that theforwarder 80 can process the address request according to the uplinkflow table.

Optionally, after the sending unit 803 sends the address request of theUE to the control device, the receiving unit 801 receives the secondinstruction information sent by the control device. In this embodiment,the second instruction information is an uplink flow table that isestablished by the control device according to the DHCP request packetin the address request, so that the forwarder 80 can send the DHCPrequest packet to the DHCP server according to the uplink flow table.

Optionally, the receiving unit 801 may also receive, in advance, thesecond instruction information sent by the control device, where thesecond instruction information includes an uplink flow table, so thatthe forwarder 80 can process an uplink packet sent by a user, and inthis embodiment, the address request sent by the UE belongs to a type ofuplink packet.

The sending unit 803 is further configured to send the DHCP request ofthe UE to the DHCP server according to the second instructioninformation.

Specifically, the sending unit 803 may decapsulate the GTP packet of theaddress request according to the uplink flow table in the secondinstruction information, and send the DHCP request packet to the DHCPserver.

Exemplarily, the second sending subunit 8023 is further configured tosend the IP address allocated to the UE and the user characteristicinformation to the control device. Specifically, because there is nocorresponding downlink flow table, the forwarder 80 sends the receivedDHCP request response that does not match any flow table to the controldevice for processing, and in order to enable the control device toidentify information about a UE side to which the IP address isallocated, the forwarder 80 sends the DHCP request response and thecorresponding user characteristic information together to the controldevice, so that the control device generates the first instructioninformation according to the IP address allocated to the UE and the usercharacteristic information, and the forwarder 80 forwards the IP addressallocated to the UE to the corresponding UE.

This embodiment provides a forwarder 80, which implements, if a controlplane is separated from a forwarding plane, a function that enables auser to acquire an IP address in a DHCP manner, and compared with otherapproaches, overcomes a disadvantage that a user cannot acquire anaddress in a DHCP manner in an SAE network architecture of SDN.

An embodiment of the present disclosure provides a control device 100,applied in a system in which a control plane of SDN is separated from aforwarding plane. A specific form of the control device is notspecifically limited in this embodiment of the present disclosure, andthe control device may be separate, or may be combined together with aforwarder. As shown in FIG. 10, the control device 100 may include anacquiring unit 1001, configured to acquire user characteristicinformation of UE and an IP address allocated to the UE, and a sendingunit 1002, configured to send first instruction information to aforwarder, where the first instruction information is used to instructthe forwarder to send, when a packet whose destination address is the IPaddress is received, the packet to the UE according to the usercharacteristic information, where the forwarder is controlled by thecontrol device 100.

Exemplarily, the user characteristic information is used to identify auser characteristic, and optionally includes TEID information or a MACaddress. Exemplarily, in this embodiment of the present disclosure, theTEID information is selected as the user characteristic information.

Exemplarily, the IP address allocated to the UE may be included in aDHCP request response. A specific form of the first instructioninformation may include a downlink flow table on which matching isperformed by using the IP address, so that the forwarder can send adownlink packet to a user using the IP address allocated to the UE, orthe control device 100 encapsulates the DHCP request response into anaddress response GTP packet, and sends the address response GTP packetto the forwarder, where a TEID, which is included in a packet header, ofthe UE is used as the first instruction information.

Further, as shown in Table 1, a flow table may include a matching field,a counter, and an instruction set, where the matching field is a10-tuple, is an input keyword for packet matching, and may match 36types of fields, which are used for header field matching, in datapacket headers at five layers from an Ethernet layer to a transmissionlayer, the counter is used to collect statistical data of a flow entry,and the instruction set indicates an operation that should be performedon a data packet matching the flow entry, and the most basic operationbehaviors include forwarding a packet to a port, forwarding a packetafter encapsulating and rewriting the packet, and discarding a packet.

If a packet entering the forwarder has a field matching the matchingfield in the flow table, the forwarder performs an operation on thepacket according to the instruction set in the flow table, if a packetentering the forwarder has no field matching the matching field in theflow table, the forwarder may send the packet to the control device 100.Generation, maintenance, and delivery of the flow table are completelyimplemented by the control device 100.

Exemplarily, referring to FIG. 11, the acquiring unit 1001 may include afirst receiving subunit 10011, configured to receive a DHCP request ofthe UE and the user characteristic information of the UE that are sentby the forwarder, where the control device supports a DHCP service, andthe user characteristic information in this embodiment is a TEID, anallocation subunit 10012, configured to allocate the IP address to theUE, where specifically, after the allocation subunit 10012 allocates theIP address to the UE, the control device 100 may map the IP addressallocated to the UE to the TEID information in a form of a mappingtable, and a delivering subunit 10013, configured to deliver the IPaddress allocated to the UE and the first instruction information to theforwarder according to the user characteristic information of the UE andthe IP address allocated to the UE.

Exemplarily, referring to FIG. 11, the acquiring unit 1001 may furtherinclude a second receiving subunit 10014, configured to receive the IPaddress allocated to the UE and the user characteristic information ofthe UE that are sent by the forwarder, and deliver the first instructioninformation to the forwarder according to the IP address allocated tothe UE and the user characteristic information of the UE.

Specifically, the second receiving subunit 10014 may include a receivingmodule 100141, configured to receive a DHCP request of the UE that issent by the forwarder, and a sending module 100142, configured to sendsecond instruction information to the forwarder, where the secondinstruction information is used to instruct the forwarder to forward,when the DHCP request is received, the DHCP request to a DHCP server.

Exemplarily, the second instruction information may be specifically anuplink flow table sent by the control device 100 to the forwarder, sothat the forwarder can process the address request according to theuplink flow table, where the second instruction information may bepreinstalled on the forwarder, or the uplink flow table may beestablished as the second instruction information according to a DHCPrequest packet in the address request after the receiving module 100141receives the address request sent by the forwarder, which is not limitedin this embodiment.

This embodiment provides a control device 100, which implements, if acontrol plane is separated from a forwarding plane, a function thatenables a user to acquire an IP address in a DHCP manner, and comparedwith other approaches, overcomes a disadvantage that a user cannotacquire an address in a DHCP manner in an SAE network architecture ofSDN.

An embodiment of the present disclosure provides a forwarder 80, appliedin a system in which a control plane of SDN is separated from aforwarding plane. A specific form of the forwarder is not specificallylimited in this embodiment of the present disclosure, and is subject toa forwarder that can implement any IP address allocation method providedin the embodiments of the present disclosure. Referring to FIG. 12, theforwarder includes at least one communications unit 1201, a processor1202, a memory 1203, and a bus 1204, where the at least onecommunications unit 1201, the processor 1202, and the memory 1203 areconnected and communicate with each other by using the bus 1204.

The bus 1204 may be an industry standard architecture (ISA) bus, aPeripheral Component Interconnect (PCI) bus, or an Extended IndustryStandard Architecture (EISA) bus. The bus 1204 may be classified into anaddress bus, a data bus, a control bus, and the like. For ease ofindication, in FIG. 12, the bus is indicated by using only one thickline, which does not indicate that there is only one bus or one type ofbus.

The memory 1203 is configured to store executable program code, wherethe program code includes a computer operation instruction. The memory1203 may include a high-speed random-access memory (RAM) memory, and mayfurther include a non-volatile memory, such as at least one magneticdisk storage. A storage device stores an operating system and anapplication program, which are configured to implement the program codein this embodiment of the present disclosure. The operating system isconfigured to control and implement a processing function executed by aprocessing unit. The application program includes the program code, suchas word processing software and email software.

The processor 1202 may be a central processing unit (CPU) or anapplication-specific integrated circuit (ASIC), or may be configured asone or more integrated circuits implementing this embodiment of thepresent disclosure.

The communications unit 1201 is configured to communicate with anexternal network element, and the processor 1202 is configured toreceive, by using the communications unit 1201, an address request sentby the external network element, where the address request includes aDHCP request of UE and user characteristic information of the UE,acquire, from a DHCP service network element according to the DHCPrequest, an IP address allocated to the UE, acquire, by using thecommunications unit 1201, first instruction information that isdelivered by a control device according to the user characteristicinformation of the UE and the IP address allocated to the UE, where thefirst instruction information is used to indicate sending, when a packetwhose destination address is the IP address allocated to the UE isreceived, the packet to the UE according to the user characteristicinformation, where the control device is a device controlling theforwarder 80, and send, to the UE according to the user characteristicinformation by using the communications unit 1201, the IP addressallocated to the UE.

Exemplarily, in this embodiment of the present disclosure, after the UEsends a DHCP request packet to an eNodeB, the eNodeB encapsulates theuser characteristic information and the DHCP request packet into a GTPpacket, to obtain the address request. The user characteristicinformation is used to identify a user characteristic, and optionallyincludes TEID information or a MAC address. Exemplarily, in thisembodiment of the present disclosure, the TEID information is selectedas the user characteristic information.

Exemplarily, the processor 1202 is further configured to send the DHCPrequest to the DHCP service network element, and receive a DHCP requestresponse sent by the DHCP service network element, where the DHCPrequest response includes the IP address allocated to the UE, and adestination address of the DHCP request response is the IP addressallocated to the UE, and the processor 1202 sends the DHCP requestresponse to the UE according to the first instruction information byusing the communications unit 1201.

Optionally, the first instruction information may include a downlinkflow table on which matching is performed by using the IP address. Theprocessor 1202 may encapsulate the DHCP request response and a TEIDtogether into a GTP packet according to the downlink flow table, andsend the GTP packet to an eNodeB by using the communications unit 1201,and finally the eNodeB decapsulates the GTP packet, and then sends theDHCP request response to the UE according to the TEID, so that the UEacquires the IP address, which is allocated to the UE, in the DHCPrequest response, thereby completing IP address allocation for the UE.

As shown in Table 1, a flow table may include a matching field, acounter, and an instruction set, where the matching field is a 10-tuple,is an input keyword for packet matching, and may match 36 types offields, which are used for header field matching, in data packet headersat five layers from an Ethernet layer to a transmission layer, thecounter is used to collect statistical data of a flow entry, and theinstruction set indicates an operation that should be performed on adata packet matching the flow entry, and the most basic operationbehaviors include forwarding a packet to a port, forwarding a packetafter encapsulating and rewriting the packet, and discarding a packet.

If a packet entering the forwarder 80 has a field matching the matchingfield in the flow table, the forwarder 80 performs an operation on thepacket according to the instruction set in the flow table, if a packetentering the forwarder 80 has no field matching the matching field inthe flow table, the forwarder 80 may send the packet to the controldevice. Generation, maintenance, and delivery of the flow table arecompletely implemented by the control device.

Optionally, the first instruction information may also be a packetheader including a TEID of the UE when the control device encapsulatesthe DHCP request response into an address response GTP packet, so thatthe processor 1202 sends, by using the communications unit 1201, theaddress response GTP packet to the corresponding UE according to thepacket header including the TEID of the UE.

Exemplarily, that the processor 1202 acquires, from a DHCP servicenetwork element according to the DHCP request, an IP address allocatedto the UE may include the processor 1202 is configured to send the DHCPrequest and the user characteristic information of the UE to the controldevice by using the communications unit 1201, where the control devicesupports a DHCP service, and receive, by using the communications unit1201, the IP address allocated to the UE and the first instructioninformation that are sent by the control device.

Further, the processor 1202 may send the DHCP request and the usercharacteristic information of the UE to the control device by using thecommunications unit 1201 after the forwarder 80 receives the addressrequest, and because an uplink flow table related to the address requestis not preinstalled, the forwarder 80 cannot find, according to theaddress request, a corresponding flow table for matching, and thereforecannot process the address request, and in this case, the forwarder 80may send all received packets that do not match any flow table to thecontrol device, and the address request is sent to the control device inthis manner, or the processor 1202 may send the DHCP request and theuser characteristic information of the UE to the control device by usingthe communications unit 1201 after the control device sends an uplinkflow table to the forwarder 80 in advance, so that the processor 1202can correspondingly process an uplink packet according to the uplinkflow table, and in this embodiment, the uplink flow table may includethat the forwarder 80 decapsulates a GTP packet of the address request,and if it is found that a decapsulated GTP packet is a DHCP requestpacket, the DHCP request packet and the TEID information in the GTPpacket of the address request are sent together to the control device.

Exemplarily, that the processor 1202 acquires, from a DHCP servicenetwork element according to the DHCP request, an IP address allocatedto the UE may also include the processor is configured to send the DHCPrequest to a DHCP server by using the communications unit 1201, andreceive, by using the communications unit 1201, the IP address that isallocated to the UE and is sent by the DHCP server, and the processor1202 is further configured to send the IP address allocated to the UEand the user characteristic information of the UE to the control deviceby using the communications unit 1201, so that the control devicedelivers the first instruction information to the forwarder 80 accordingto the IP address allocated to the UE and the user characteristicinformation.

Further, before the processor 1202 sends, to the DHCP server by usingthe communications unit 1201, the request for acquiring an address ofthe UE, the processor 1202 is further configured to send the DHCPrequest of the UE to the control device by using the communications unit1201, and receive, by using the communications unit 1201, secondinstruction information sent by the control device, where the secondinstruction information is used to indicate forwarding, when the addressrequest of the UE is received, the DHCP request of the UE to the DHCPserver.

Specifically, the second instruction information may be an uplink flowtable sent by the control device to the forwarder 80, so that theforwarder 80 can process the address request according to the uplinkflow table.

Optionally, after sending the address request of the UE to the controldevice by using the communications unit 1201, the processor 1202 mayreceive, by using the communications unit 1201, the second instructioninformation sent by the control device, and in this case, the secondinstruction information is an uplink flow table that is established bythe control device according to the DHCP request packet in the addressrequest, so that the forwarder 80 can send the DHCP request packet tothe DHCP server according to the uplink flow table.

Optionally, the processor 1202 may also receive, in advance by using thecommunications unit 1201, the second instruction information sent by thecontrol device, where the second instruction information includes anuplink flow table, so that the forwarder 80 can process an uplink packetsent by a user, and in this embodiment, the address request sent by theUE belongs to a type of uplink packet.

Exemplarily, the processor 1202 may be configured to send the DHCPrequest of the UE to the DHCP server according to the second instructioninformation by using the communications unit 1201. Specifically, theprocessor 1202 may decapsulate the GTP packet of the address requestaccording to the uplink flow table in the second instructioninformation, and send the DHCP request packet to the DHCP server.

Exemplarily, the processor 1202 sends, by using the communications unit1201, the IP address allocated to the UE and the user characteristicinformation to the control device. Specifically, because there is nocorresponding downlink flow table, the forwarder 80 sends the receivedDHCP request response that does not match any flow table to the controldevice for processing, and in order to enable the control device toidentify information about a UE side to which the IP address isallocated, the forwarder 80 sends the DHCP request response and thecorresponding user characteristic information together to the controldevice, so that the control device generates the first instructioninformation according to the IP address allocated to the UE and theTEID, and the forwarder 80 forwards the IP address allocated to the UEto the corresponding UE.

This embodiment provides a forwarder 80, which implements, if a controlplane is separated from a forwarding plane, a function that enables auser to acquire an IP address in a DHCP manner, and compared with otherapproaches, overcomes a disadvantage that a user cannot acquire anaddress in a DHCP manner in an SAE network architecture of SDN.

An embodiment of the present disclosure provides a control device 100,applied in a system in which a control plane of SDN is separated from aforwarding plane. A specific form of the control device 100 is notspecifically limited in this embodiment of the present disclosure, andthe control device may be separate, or may be combined together with aforwarder. As shown in FIG. 13, the control device 100 may include atleast one communications unit 1301, a processor 1302, a memory 1303, anda bus 1304, where the at least one communications unit 1301, theprocessor 1302, and the memory 1303 are connected and communicate witheach other by using the bus 1304.

The bus 1304 may be an ISA bus, a PCI bus, or an EISA bus. The bus 1304may be classified into an address bus, a data bus, a control bus, andthe like. For ease of indication, in FIG. 12, the bus is indicated byusing only one thick line, which does not indicate that there is onlyone bus or one type of bus.

The memory 1303 is configured to store executable program code, wherethe program code includes a computer operation instruction. The memory1303 may include a high-speed RAM memory, and may further include anon-volatile memory, such as at least one magnetic disk storage. Astorage device stores an operating system and an application program,which are configured to implement the program code in this embodiment ofthe present disclosure. The operating system is configured to controland implement a processing function executed by a processing unit. Theapplication program includes the program code, such as word processingsoftware and email software.

The processor 1302 may be a CPU or an ASIC, or may be configured as oneor more integrated circuits implementing this embodiment of the presentdisclosure.

The communications unit 1301 is configured to communicate with anexternal network element, and the processor 1302 is configured toacquire user characteristic information of UE and an IP addressallocated to the UE, and send first instruction information to aforwarder by using the communications unit 1301, where the firstinstruction information is used to indicate sending, when a packet whosedestination address is the IP address is received, the packet to the UEaccording to the user characteristic information, where the forwarder iscontrolled by the control device 100.

Exemplarily, the user characteristic information is used to identify auser characteristic, and optionally includes TEID information or a MACaddress. Exemplarily, in this embodiment of the present disclosure, theTEID information is selected as the user characteristic information.

Exemplarily, the IP address allocated to the UE may be included in aDHCP request response. The first instruction information mayspecifically include a downlink flow table on which matching isperformed by using the IP address, so that the forwarder can send adownlink packet to a user using the IP address allocated to the UE, orthe control device 100 encapsulates the DHCP request response into anaddress response GTP packet, and sends the address response GTP packetto the forwarder, where a TEID, which is included in a packet header, ofa UE side is used as the first instruction information.

Further, as shown in Table 1, a flow table may include a matching field,a counter, and an instruction set, where the matching field is a10-tuple, is an input keyword for packet matching, and may match 36types of fields, which are used for header field matching, in datapacket headers at five layers from an Ethernet layer to a transmissionlayer, the counter is used to collect statistical data of a flow entry,and the instruction set indicates an operation that should be performedon a data packet matching the flow entry, and the most basic operationbehaviors include forwarding a packet to a port, forwarding a packetafter encapsulating and rewriting the packet, and discarding a packet.

If a packet entering the forwarder has a field matching the matchingfield in the flow table, the forwarder performs an operation on thepacket according to the instruction set in the flow table, if a packetentering the forwarder has no field matching the matching field in theflow table, the forwarder may send the packet to the control device 100.Generation, maintenance, and delivery of the flow table are completelyimplemented by the control device 100.

Exemplarily, that the processor 1302 is configured to acquire usercharacteristic information of UE and an IP address allocated to the UEspecifically includes the processor 1302 is configured to receive, byusing the communications unit 1301, a DHCP request of the UE and theuser characteristic information of the UE that are sent by theforwarder, where the control device supports a DHCP service, and theuser characteristic information in this embodiment is a TEID, allocatethe IP address to the UE, where specifically, after allocating the IPaddress to the UE, the processor 1302 may map the IP address allocatedto the UE to the TEID information in a form of a mapping table, anddeliver the IP address allocated to the UE and the first instructioninformation to the forwarder according to the user characteristicinformation of the UE and the IP address allocated to the UE.

Exemplarily, that the processor 1302 is configured to acquire usercharacteristic information of UE and an IP address allocated to the UEspecifically includes receiving, by the processor 1302 by using thecommunications unit 1301, the IP address allocated to the UE and theuser characteristic information of the UE that are sent by theforwarder, and delivering the first instruction information to theforwarder according to the IP address allocated to the UE and the usercharacteristic information of the UE.

Further, the processor 1302 is further configured to receive, by usingthe communications unit 1301, a DHCP request of the UE that is sent bythe forwarder, and send second instruction information to the forwarderby using the communications unit 1301, where the second instructioninformation is used to instruct the forwarder to forward, when the DHCPrequest is received, the DHCP request to a DHCP server.

Exemplarily, the second instruction information may be specifically anuplink flow table sent by the control device 100 to the forwarder, sothat the forwarder can process an address request according to theuplink flow table, where the second instruction information may bepreinstalled on the forwarder, or the uplink flow table may beestablished as the second instruction information according to a DHCPrequest packet in the address request after the processor 1302 receives,by using the communications unit 1301, the address request sent by theforwarder, which is not limited in this embodiment.

This embodiment provides a control device 100, which implements, if acontrol plane is separated from a forwarding plane, a function thatenables a user to acquire an IP address in a DHCP manner, and comparedwith other approaches, overcomes a disadvantage that a user cannotacquire an address in a DHCP manner in an SAE network architecture ofSDN.

An embodiment of the present disclosure provides an IP addressallocation system. As shown in FIG. 14, the IP address allocation systemimplements separation between a control plane and a forwarding plane,and includes a forwarder 80 and a control device 100, where theforwarder 80 is any forwarder shown in FIG. 8 and FIG. 9, and thecontrol device 100 is any control device shown in FIG. 10 and FIG. 11,or the forwarder 80 is the forwarder shown in FIG. 12, and the controldevice 100 is the control device shown in FIG. 13.

This embodiment provides an IP address allocation system, whichimplements, if a control plane is separated from a forwarding plane, afunction that enables a user to acquire an IP address in a DHCP manner,and compared with other approaches, overcomes a disadvantage that a usercannot acquire an address in a DHCP manner in an SAE networkarchitecture of SDN.

In the several embodiments provided in the present application, itshould be understood that the disclosed system, apparatus, and methodmay be implemented in other manners. For example, the describedapparatus embodiment is merely exemplary. For example, the unit divisionis merely logical function division and may be other division in actualimplementation. For example, a plurality of units or components may becombined or integrated into another system, or some features may beignored or not performed. In addition, the displayed or discussed mutualcouplings or direct couplings or communication connections may beimplemented by using some interfaces. The indirect couplings orcommunication connections between the apparatuses or units may beimplemented in an electronic form, a mechanical form, or another form.

The units described as separate parts may or may not be physicallyseparate, and parts displayed as units may or may not be physical units,may be located in one position, or may be distributed on a plurality ofnetwork units. Some or all of the units may be selected according toactual needs to achieve the objectives of the solutions of theembodiments.

In addition, functional units in the embodiments of the presentdisclosure may be integrated into one processing unit, or each of theunits may exist alone physically, or two or more units are integratedinto one unit. The foregoing integrated unit may be implemented in aform of hardware, or may be implemented in a form of hardware inaddition to a software functional unit.

The foregoing integrated unit that is implemented in a form of asoftware functional unit may be stored in a computer-readable storagemedium. The foregoing software functional unit is stored in a storagemedium and includes several instructions for instructing a computerdevice (which may be a personal computer, a server, a network device, orthe like) to perform some of the steps of the methods described in theembodiments of the present disclosure. The foregoing storage mediumincludes any medium that can store program code, such as a universalserial bus (USB) flash drive, a removable hard disk, a read-only memory(ROM), a RAM, a magnetic disk, or an optical disc.

Finally, it should be noted that the foregoing embodiments are merelyintended for describing the technical solutions of the presentdisclosure but not for limiting the present disclosure. Although thepresent disclosure is described in detail with reference to theforegoing embodiments, persons of ordinary skill in the art shouldunderstand that they may still make modifications to the technicalsolutions described in the foregoing embodiments or make equivalentreplacements to some technical features thereof, as long as suchmodifications or replacements do not cause the essence of correspondingtechnical solutions to depart from the scope of the technical solutionsof the embodiments of the present disclosure.

1-14. (canceled)
 15. A communications system in which a control plane isseparated from a forwarding plane, wherein the communications systemnetwork comprises: a control device; and a forwarder configured to:receive Dynamic Host Configuration Protocol (DHCP) information of a userequipment (UE) and user characteristic information of the UE; send theDHCP information and the user characteristic information to the controldevice; receive, from the control device, an Internet Protocol (IP)address allocated to the UE and first information comprising a downlinkflow table comprising the IP address indicating to the forwarder to senda packet to the UE when an address of the packet is the IP address; andsend the IP address to the UE according to the first information. 16.The communications system of claim 15, wherein the forwarder is furtherconfigured to: receive the packet, wherein a destination address of thepacket is the IP address; and send the packet to the UE according to thedownlink flow table.
 17. The communications system of claim 15, whereinthe control device is configured to: receive the DHCP information andthe user characteristic information from the forwarder; and send the IPaddress and the first information to the forwarder.
 18. Thecommunications system of claim 15, further comprising a network deviceconfigured to send the DHCP information to the forwarder.
 19. Thecommunications system of claim 15, wherein the downlink flow tablecomprises a matching field comprising the IP address and an instructionset corresponding to the matching field.
 20. The communications systemof claim 19, wherein the instruction set instructs to send the packet tothe UE.
 21. An address allocation method applied in a system in which acontrol plane is separated from a forwarding plane, wherein the methodcomprises: acquiring, by a control device, user characteristicinformation of a user equipment (UE) and an Internet Protocol (IP)address allocated to the UE; and sending, by the control device to aforwarder, first information comprising a downlink flow table comprisingthe IP address indicating to the forwarder to send a packet to the UEwhen an address of the packet is the IP address, wherein the forwarderis controlled by the control device.
 22. The address allocation methodof claim 21, wherein acquiring the user characteristic information andthe IP address comprises receiving, by the control device, the IPaddress and the user characteristic information from the forwarder. 23.The address allocation method of claim 22, wherein receiving the IPaddress and the user characteristic information comprises: receivingDHCP information of the UE from the forwarder; and sending, to theforwarder, second information indicating to the forwarder to forward theDHCP information to a DHCP server when the DHCP information is received.24. The address allocation method of claim 21, wherein sending the firstinformation comprises sending the first information to the forwarderaccording to the IP address and the user characteristic information. 25.The address allocation method of claim 21, wherein acquiring the usercharacteristic information and the IP address comprises: receivingDynamic Host Configuration Protocol (DHCP) information of the UE and theuser characteristic information from the forwarder; and allocating theIP address to the UE.
 26. The address allocation method of claim 21,wherein the downlink flow table comprises a matching field comprisingthe IP address and an instruction set corresponding to the matchingfield.
 27. The address allocation method of claim 26, wherein theinstruction set instructs to send the packet to the UE.
 28. A controldevice of a core network for a system in which a control plane isseparated from a forwarding plane, wherein the control device comprises:a processor; and a memory coupled to the processor, wherein the memorycomprises instructions executable by the processor to cause the controldevice to: acquire user characteristic information of a user equipment(UE) and an internet protocol (IP) address allocated to the UE; and sendfirst information to a forwarder comprising a downlink flow tablecomprising the IP address indicating the forwarder to send, a packet tothe UE when an address of the packet is the IP address, wherein theforwarder is controlled by the control device.
 29. The control device ofclaim 28, wherein the instructions further cause the control device toreceive the IP address and the user characteristic information from theforwarder.
 30. The control device of claim 28, wherein the instructionsfurther cause the control device to send the first information to theforwarder according to the IP address and the user characteristicinformation.
 31. The control device of claim 28, wherein theinstructions further cause the control device to: receive, from theforwarder, dynamic host configuration protocol (DHCP) information of theUE and the user characteristic information; and allocate the IP addressto the UE.
 32. The control device of claim 28, wherein the instructionsfurther cause the control device to: receive the DHCP information; andsend, to the forwarder, second information indicating the forwarder toforward the DHCP information to a DHCP server when the DHCP informationis received.
 33. The control device of claim 28, wherein the downlinkflow table comprises a matching field comprising the IP address and aninstruction set corresponding to the matching field.
 34. The controldevice of claim 33, wherein the instruction set instructs to send thepacket to the UE.